GENOTYPIC STRUCTURE OF THE BUUBEI AND ZABAIKALSKAYA BREED SHEEP ACCORDING TO THE GENES GDF9, CAST, KRT1.2, KAP1.3 AND THEIR RELATIONSHIP WITH PRODUCTIVITY

The purpose of this study is to identify the polymorphism of the GDF9, CAST, KRT1.2, KAP1.3 genes and to study their influence on the live weight and wool productivity of the Zabaikalskaya fine-wool breed and coarse-wooled Buubei sheep. The scientific novelty lies in the fact that for the first time a comparative evaluation of the genotypic features of sheep by SNP-markers and their association with productivity in the breeds has been carried out. The object of the study were sheep of the Zabaikalskaya fine-wool breed (100 heads) and coarse-wooled Buubei breed (60 heads). As a result of the research, it was found that for the genes GDF9/G1 and CAST the breeds have almost the same ratio of genotypes and alleles, for the genes KRT1.2 and KAP1.3 significant differences were found. The Buubei breed is characterized by a 17.7 % higher content of the KRT1.2MM genotype and a 15.7 % lower frequency of the KRT1.2MN genotype compared to the Zabaikalskaya fine-wool breed. The genotype frequency of the KAP1.3 gene in the Buubei breed was found in the ratio (26.7:46.6:26.7), in the Zabaikalskaya breed (61.6:36.0:3.0). The gene equilibrium in the herds is not disturbed (χ2= 0,006 - 0,713). There is no inbreeding in the herds (Fis – 0.0037 to +0.066), PIC is in the range from 0.192. to 0.203. The homozygosity coefficient SH – 17,7 and 9,5 %, Naj -1,32 and 1,27. It was found that rams with CASTMM genotype have higher live weight by 20.2 kg compared to the heterozygous animals. Buubei sheep with the KRT1.2MM genotype had 0.58 cm longer down than the animals with the KRT1.2MN heterozygous genotype. No priority genotypes associated with productivity have been identified in the Zabaikalskaya breed. The established structure of the Zabaikalskaya and Buubei breeds can serve as a basis for monitoring the genotypic structure of these breeds and in comparative evaluation with other Siberian breeds. The identified associative relationships of the genetic markers with wool productivity can be successfully used as additional criteria for selection of sheep for breeding traits.